Method for obtaining adhesion of urethane sealant to a painted or glass surface

Abstract

A method is disclosed for treatment of a painted or a glass surface providing improved adhesion of a urethane sealant applied thereafter, comprising applying a solution containing p-toluenesulfonic acid, optionally an organofunctional silane, and an appropriate solvent to the painted or the glass surface, the painted surface being cured and devoid of a resin coating, and thereafter contacting the painted or the glass surface with the urethane sealant. A method for joining painted and glass surfaces using a urethane sealant is also disclosed. Compositions useful within these methods are also described.

What is claimed is: 
     
       1. A method for treatment of a painted surface of a substrate or a glass surface so as to provide improved adhesion of a urethane sealant applied thereafter, comprising: applying a solution of from about 0.25% to about 5% by weight p-toluenesulfonic acid, about 2.5% by weight organofunctional silane, and from about 92.5% to about 97.25% by weight of a solvent selected from the group consisting of ketones, alcohols and aliphatic esters to the painted or the glass surface, the painted surface being cured and devoid of a resin top coating; and   thereafter contacting the painted or glass surface with an uncured urethane sealant.   
     
     
       2. The method of claim 1 wherein the appropriate solvent is selected from the group consisting of methyl ethyl ketone, isopropanol, and ethyl acetate. 
     
     
       3. The method of claim 1 wherein the organofunctional silane is gamma-mercaptopropyltrimethoxysilane. 
     
     
       4. The method of claim 1 wherein the solution is about 1% by weight p-toluenesulfonic acid, about 2.5% by weight gamma-mercaptopropyltrimethoxysilane, and about 96.5% by weight isopropanol. 
     
     
       5. The method of claim 1 wherein the painted surface is coated with cured enamel paint. 
     
     
       6. The method of claim 1 wherein the uncured urethane sealant is a one-part heat or moisture curable system. 
     
     
       7. The method of claim 1 wherein the uncured urethane sealant is a two-part heat or chemically activatable system. 
     
     
       8. The method of claim 1 wherein the step of applying is performed by wiping the solution over the painted or the glass surface with a cloth. 
     
     
       9. The method of claim 1 wherein the step of applying is performed by spraying the solution over the painted or the glass surface. 
     
     
       10. The method of claim 1 comprising the further step of thereafter allowing said uncured urethane to cure. 
     
     
       11. A method for treatment of a painted surface of a substrate so as to provide improved adhesion of a urethane sealant applied thereafter, comprising: applying a solution of from about 0.25% to about 5% by weight p-toluenesulfonic acid and from about 95% to about 99.75% by weight of a solvent selected from the group consisting of ketones, alcohols and aliphatic esters to the painted surface, said painted surface being cured and devoid of a resin top coating; and   thereafter contacting the painted surface with an uncured urethane sealant.   
     
     
       12. The method of claim 11 wherein the appropriate solvent is selected from the group consisting of methyl ethyl ketone, isopropanol, and ethyl acetate. 
     
     
       13. The method of claim 11 wherein the painted surface is coated with cured enamel paint. 
     
     
       14. The method of claim 11 wherein the uncured urethane sealant is a one-part heat or moisture curable system. 
     
     
       15. The method of claim 11 wherein the uncured urethane sealant is a two-part heat or chemically activatable system. 
     
     
       16. The method of claim 11 wherein the step of applying is performed by wiping the solution over the painted surface with a cloth. 
     
     
       17. The method of claim 11 wherein the step of applying is performed by spraying the solution over the painted surface. 
     
     
       18. The method of claim 11 comprising the further step of allowing said uncured urethane to cure. 
     
     
       19. A method for joining a painted surface and a glass surface comprising: applying a first solution of from about 0.25% to about 5% by weight p-toluenesulfonic acid and from about 95% to about 99.75% by weight of a solvent selected from the group consisting of ketones, alchohols and aliphatic esters to the painted surface, said painted surface being cured and devoid of a resin coating;   contacting the painted surface with an uncured urethane sealant;   applying a second solution of from about 0.25% to about 5% by weight p-toluenesulfonic acid, about 2.5% by weight organofunctional silane, and from about 92.5% to about 97.25% by weight of a solvent selected from the group consisting of ketones, alchohols and aliphatic esters to the glass surface;   joining the glass surface to the uncured urethane sealant; and   allowing the urethane sealant to cure.   
     
     
       20. The method of claim 19 wherein the first solution is about 1% by weight p-toluenesulfonic acid and about 99% by weight methyl ethyl ketone, isopropanol, or ethyl acetate. 
     
     
       21. The method of claim 19 wherein the first solution is about 1% by weight p-toluenesulfonic acid, about 2.5% by weight organofunctional silane, and about 96.5% by weight isopropanol. 
     
     
       22. The method of claim 19 wherein the second solution is about 1% by weight p-toluenesulfonic acid, about 2.5% by weight gamma-mercaptopropyltrimethoxysilane, and about 96.5% by weight isopropanol. 
     
     
       23. A composition for treatment of a painted or a glass surface that provides improved adhesion of a urethane sealant applied thereafter, comprising: from about 0.25% to about 5% by weight p-toluenesulfonic acid;   about 2.5% by weight organofunctional silane; and   from about 92.5% to about 97.25% by weight of a solvent selected from the group consisting of ketones, alchohols and aliphatic esters.   
     
     
       24. The composition of claim 23 wherein the appropriate solvent is selected from the group consisting of methyl ethyl ketone, isopropanol, and ethyl acetate. 
     
     
       25. The composition of claim 23 that is about 1% by weight p-toluenesulfonic acid, about 2.5% by weight organofunctional silane, and about 96.5% by weight methyl ethyl ketone, isopropanol, or ethyl acetate. 
     
     
       26. The composition of claim 26 wherein the organofunctional silane is gamma-mercaptopropyltrimethoxysilane.